The technical data sheet of the keyboard says this:
"Right side of space bar has typical space bar functionality; left side of space bar will toggle between backspace functionality and typical space bar functionality. To activate, depress and hold both sides of space bar for 3 seconds."
This suggests it is a built-in feature of the keyboard and does not require a driver. If you activate this feature,
showkeys will most likely report the scancode for the backspace if you hit the left space bar (in which case you're still out of luck). If, on the other hand, the keyboard does happen to give off two different scancodes for the left space bar and the real backspace, you can map that keycode to an Enter. Keyboard mappings kan be manipulated with tools like xkbcomp or make your own mapping. Beware however, that the handling of keycodes by X is highly esoteric and documentation is ... rather terse. A start is the documentation of xkbcomp.
BTW, note that the reported keycodes "0x39 0xb9" are for the same key, the latter just has the high bit set to indicate key release. 0x39 is 57 decimal, which maps to the Space key in X for PC keyboards.